Glass Member Having Photocatalytic Function and Heat Reflecting Function and Double Paned Glass Including The Same

ABSTRACT

The present invention provides a glass member including a photocatalyst layer and a heat reflecting layer, the glass member having high photocatalytic activity and exhibiting a low reflectance and a colorless or pale blue reflection color tone or a bluish green or green reflection color tone. The glass member is produced by laminating an antistripping layer made of silicon oxide or the like, a crystalline undercoat layer made of zirconium oxide or the like and a photocatalyst layer made of titanium oxide or the like on the other surface of a glass substrate having a heat reflecting layer formed on one surface thereof. The heat reflecting layer is formed such that the other surface of the glass substrate has a reflection chromaticity (a*, b*) satisfying −4≦a*≦2 and −5≦b*≦0 and a visible light reflectance of 10% or less, the crystalline undercoat layer is allowed to have a thickness ranging from 2 to 28 nm, and the photocatalyst layer is allowed to have a thickness ranging from 2 to 20 nm, whereby the glass member having a colorless or pale blue reflection color tone can be produced. Likewise, the heat reflecting layer is formed such that the reflection chromaticity (a*, b*) satisfies −15≦a*≦−2 and −10≦b*≦10 and the visible light reflectance is 13% or less, the crystalline undercoat layer is allowed to have a thickness ranging from 2 to 28 nm, and the photocatalyst layer is allowed to have a thickness ranging from 2 to 14 nm, whereby the glass member having a bluish green or green reflection color tone can be produced.

TECHNICAL FIELD

The present invention relates to a glass member having a heat reflectinglayer laminated on one surface of a glass substrate and a photocatalyticlayer laminated on the other surface thereof, and to double paned glassincluding the same.

BACKGROUND ART

Photocatalysts such as anatase type titanium oxide are known to exhibitan antifouling effect to decompose organic materials under ultravioletlight irradiation, antibacterial activity and hydrophilicity. Recently,photocatalysts that exhibit a catalytic function under visible lightirradiation have also attracted attention. To impart such aphotocatalytic function to a substrate such as glass, a photocatalystlayer is placed on a surface of the substrate. As the formation method,vacuum film formation methods such as sputtering and vapor deposition,and reduced pressure film formation methods are widely used.

When forming a photocatalyst layer on a surface of a substrate such asglass as just described, a method is proposed to place an undercoatlayer between the substrate and the photocatalyst layer (PatentDocuments 1 to 7).

Patent Document 1 discloses a method in which, when forming a mediumcomprising a photocatalytic composition on a surface of a glasssubstrate, an undercoat layer is formed between the glass substrate andthe medium so as to prevent deterioration of the mediums function causedby alkali eluted from the glass. This document proposes to use, forexample, zirconium oxide, in particular, amorphous zirconium oxide asthe undercoat layer. Patent Document 2 discloses the use of zirconiumoxide as an undercoat layer formed between a substrate and aphotocatalyst layer and the use of titanium oxide as the photocatalystlayer. Patent document 3 discloses a method in which a metal oxide layercontaining zirconium oxide is placed between a substrate and aphotocatalyst layer so that the metal oxide layer suppresses thediffusion of oxygen from the photocatalyst layer to the substrate.Patent Document 4 discloses a similar method in which a zirconium oxidelayer is formed between a substrate and a titanium oxide layer. PatentDocument 5 discloses the use of zirconium oxide whose crystal systembelongs to a monoclinic system as an undercoat layer and the use ofanatase type titanium oxide as a photocatalyst layer.

Patent Documents 6 and 7 disclose the relationship of undercoat layerand photocatalyst layer thicknesses with optical properties. PatentDocument 6 discloses a layer containing tin oxide (SnO₂) and zirconiumoxide (ZrO₂) and having a thickness of 10 nm or less as an undercoatlayer and a layer containing titanium oxide (TiO₂) having a thickness of20 nm or less as a photocatalyst layer. This document teaches that it isnecessary to reduce the thickness of both layers to impart transparencyto the resulting glass member. Patent document 7 discloses a techniqueof forming a layer made of high temperature stable cubic or orthorhombiczirconium oxide between a substrate and a titanium oxide layer, andteaches that, when used in automobiles and the like, the thickness ofthe titanium oxide layer has to be such that the other side can be seentherethrough.

On the other hand, double paned glass is reported that includes a glassmember comprising a heat reflecting layer laminated on one surface of aglass substrate and a photocatalyst layer on the other surface thereof(Patent Document 8). Double paned glass usually has two glass plates (anoutdoor side glass plate and an indoor side glass plate) with a spacerplaced between the two glass plates so as to create a spacetherebetween. A glass member as described above is used as an outdoorside glass plate, and is placed such that the photocatalyst layer servesas the outermost layer of the double paned glass and the heat reflectinglayer faces the inner side of the double paned glass.

Patent Document 1: JP H09-227167A

Patent Document 2: JP H10-66878A

Patent Document 3: JP 2000-312830A

Patent Document 4: JP 2001-205094A

Patent Document 5: WO 03/53577

Patent Document 6: JP 2000-513695

Patent Document 7: WO 02/40417

Patent Document 8: WO 02/62716

DISCLOSURE OF INVENTION Problem to be Solved by the Invention

However, when a photocatalyst layer is formed according to the methodsdisclosed in Patent Documents 1 to 4 and 6, problems arise in that thephotocatalyst layer may not provide a sufficient photocatalyticfunction. Further, unless the thickness of the photocatalyst layer isincreased, then the photocatalyst layer does not sufficiently functionas a photocatalyst layer and the resulting glass member will have a highreflectance, or interference colors will appear. For this reason, it hasbeen difficult for a glass member including a photocatalyst layerlaminated thereon to provide a photocatalytic function while achievingdesirable reflectance and color tone.

Moreover, in the double paned glass including a glass member having aheat reflecting layer formed thereon described above, because theoutdoor side (photocatalyst layer side) glass plate has a highreflectance, it has been difficult to produce double paned glass whosereflection color tone viewing from outside is colorless or slightlyblue, or a bluish green or green.

In view of the above, it is an object of the present invention toprovide a glass member and a double paned glass, the glass member andthe double paned glass including a heat reflecting layer and aphotocatalyst layer, the photocatalyst layer having high photocatalyticactivity and the photocatalyst layer side surface being capable ofexhibiting a low reflectance along with a colorless or pale bluereflection color tone, or a bluish green or green reflection color tone.

MEANS FOR SOLVING PROBLEM

In order to achieve the above object, a glass member according to afirst embodiment of the present invention is a glass member in which aheat reflecting layer is laminated on one surface of a glass substrateand a photocatalyst layer is laminated on the other surface thereof,wherein the glass substrate and the heat reflecting layer are combinedsuch that, in a state in which the heat reflecting layer is laminated onone surface of the glass substrate and the photocatalyst layer is notlaminated on the other surface of the glass substrate (hereinaftersometimes referred to as “single plate”), the other surface of the glasssubstrate has a reflection chromaticity (a*, b*) satisfying −4≦a*≦2 and−5≦b*≦0 and a visible light reflectance of 10% or less, an antistrippinglayer, a crystalline undercoat layer and the photocatalyst layer arelaminated in this order on the other surface of the glass substrate, thecrystalline undercoat layer has a thickness ranging from 2 to 28 nm, thephotocatalyst layer has a thickness ranging from 2 to 20 nm, and theantistripping layer comprises at least one material selected from thegroup consisting of an oxide, an oxynitride and a nitride containing atleast one of silicon and tin.

A glass member according to a second embodiment of the present inventionis a glass member in which a heat reflecting layer is laminated on onesurface of a glass substrate and a photocatalyst layer is laminated onthe other surface thereof, wherein the glass substrate and the heatreflecting layer are combined such that the other surface of the glasssubstrate of the single plate has a reflection chromaticity (a*, b*)satisfying −15≦a*≦−2 and −10≦b*≦10 and a visible light reflectance of13% or less, a crystalline undercoat layer has a thickness ranging from2 to 28 nm, the photocatalyst layer has a thickness ranging from 2 to 14nm, and the antistripping layer comprises at least one material selectedfrom the group consisting of an oxide, an oxynitride and a nitridecontaining at least one of silicon and tin.

Double paned glass of the present invention comprises two glass platesand a spacer placed between the two glass plates so as to create a spacebetween the facing surfaces of the two glass plates, wherein at leastone of the glass plates is a glass member of the present invention, andthe photocatalyst layer of the glass member is placed such that thephotocatalyst layer serves as an outermost layer of the double panedglass.

EFFECTS OF THE INVENTION

According to the glass member of the present invention, when a heatreflecting layer is laminated on a glass substrate, specifically, evenwhen the single plate has the characteristics: the reflectionchromaticity (a*, b*) of the other surface of the glass substrate is−4≦a*≦2 and −5≦b*≦0 and the visible light reflectance of the same is 10%or less, it is possible to realize a low reflectance and a colorless orpale blue reflection color tone as well as to obtain excellentphotocatalytic activity. Also, even when the single plate has thecharacteristics: the reflection chromaticity (a*, b*) of the othersurface of the glass substrate is −15≦a*≦−2 and −10≦b*≦10 and thevisible light reflectance is 13% or less, it is possible to realize alow reflectance and a bluish green or green reflection color tone aswell as to obtain excellent photocatalytic activity. Thus, according tothe double paned glass including the glass member of the presentinvention, it is possible to achieve high photocatalytic activity whileachieving excellent reflectance and reflection color tone for thephotocatalyst layer side surface. Therefore, it is suitable for use asdouble paned glass for large construction use that requires excellentphotocatalytic function and a clear appearance.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross sectional view showing an example of a glass member ofthe present invention.

FIG. 2 is a cross sectional view showing an example of double panedglass of the present invention.

FIG. 3 is a graph showing photocatalyst layer thickness change versusreflectance of double paned glass obtained in an example of the presentinvention.

FIG. 4 is a graph showing crystalline undercoat layer thickness changeversus reflectance of double paned glass obtained in another example ofthe present invention.

FIG. 5 is a graph showing photocatalyst layer thickness change versusreflection chromaticity of double paned glass obtained in still anotherexample of the present invention.

FIG. 6 is a graph showing photocatalyst layer thickness change versusreflection chromaticity of double paned glass obtained in still anotherexample of the present invention.

FIG. 7 is a graph showing crystalline undercoat layer thickness changeversus reflection chromaticity of double paned glass obtained in stillanother example of the present invention.

FIG. 8 is a graph showing crystalline undercoat layer thickness changeversus reflection chromaticity of double paned glass obtained in stillanother example of the present invention.

FIG. 9 is a graph showing photocatalyst layer thickness change versusreflectance of double paned glass obtained in still another example ofthe present invention.

FIG. 10 is a graph showing crystalline undercoat layer thickness changeversus reflectance of double paned glass obtained in still anotherexample of the present invention.

FIG. 11 is a graph showing photocatalyst layer thickness change versusreflection chromaticity of double paned glass obtained in still anotherexample of the present invention.

FIG. 12 is a graph showing photocatalyst layer thickness change versusreflection chromaticity of double paned glass obtained in still anotherexample of the present invention.

FIG. 13 is a graph showing crystalline undercoat layer thickness changeversus reflection chromaticity of double paned glass obtained in stillanother example of the present invention.

FIG. 14 is a graph showing crystalline undercoat layer thickness changeversus reflection chromaticity of double paned glass obtained in stillanother example of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

An example of the glass member of the present invention will bedescribed with reference to FIG. 1. However, it is to be understood thatthe shape and size of the glass member of the present invention is notlimited to those given below.

FIG. 1 is a cross sectional view of an example of the glass member ofthe present invention. In a glass member 30, a heat reflecting layer 14is laminated on one surface of a glass substrate 10. On the othersurface thereof, an antistripping layer 1, a crystalline undercoat layer2 and a photocatalyst layer 3 are laminated in this order. As usedherein, the “crystalline” means a state in which a lattice fringe orelectron diffraction image is observed when, for example, a crosssection of the laminated layer is observed by a transmission electronmicroscope.

In the case of a glass member according to the first embodiment of thepresent invention, when the heat reflecting layer 14 is laminated on onesurface of the glass substrate 10, the other surface of the glasssubstrate 10 has a combination of a reflection chromaticity (a*, b*)satisfying −4≦a*≦2 and −5≦b*≦0 and a visible light reflectance of 10% orless. In this case, the crystalline undercoat layer 2 has a thicknessranging from 2 to 28 nm. The photocatalyst layer 3 has a thicknessranging from 2 to 20 nm. The antistripping layer 1 includes at least oneselected from the group consisting of an oxide, an oxynitride and anitride containing at least one of silicon and tin.

In the case of a glass member according to the second embodiment of thepresent invention, when the heat reflecting layer 14 is laminated on onesurface of the glass substrate 10, the other surface of the glasssubstrate 10 has a combination of a reflection chromaticity (a*, b*)satisfying −15≦a*≦−2 and −10≦b*≦10 and a visible light reflectance of13% or less. In this case, the crystalline undercoat layer 2 has athickness ranging from 2 to 28 nm. The photocatalyst layer 3 has athickness ranging from 2 to 14 nm. The antistripping layer 1 includes atleast one selected from the group consisting of an oxide, an oxynitrideand a nitride containing at least one of silicon and tin.

As a result of extensive and thorough studies, the present inventorsobtained the following findings, and the present invention has beenaccomplished. The present inventors analyzed the structures of the crosssections of photocatalyst layers having the same thickness, but with andwithout photocatalytic activity, using an electron microscope. As aresult, they found that the photocatalytic activity depends on thecrystallinity of the photocatalyst layer. More specifically, they foundthat a photocatalyst layer whose crystal structure extends clearly andcontinuously from the interface with the substrate to the surface of thephotocatalyst layer provides significant photocatalytic activity,whereas a photocatalyst layer in which no crystalline structure isobserved near the interface with the substrate, and a non-crystalline(amorphous) layer (hereinafter referred to as “dead layer”) is formeddoes not exhibit sufficient photocatalytic activity. On the basis ofthis finding, they found that, by forming a crystalline undercoat layeron the substrate in order to facilitate the crystal growth of aphotocatalyst layer, and forming a photocatalyst layer on the surface ofthe crystalline undercoat layer, it is possible to suppress theformation of a dead layer. As used herein, the “dead layer” refers to alayer having typical non-crystalline (amorphous) characteristics. When aphotocatalyst layer having a dead layer is irradiated by an electronbeam, a halo pattern is observed in the electron diffraction image. Whena photocatalyst layer substantially having no dead layer is irradiatedby an electron beam, electron diffraction spots are observed.

However, even in a photocatalyst layer without the dead layer asdescribed above, when a crystal structure is formed continuously fromthe interface of the crystalline undercoat layer to the surface of thephotocatalyst layer, for example, ions having a small ionic radius(e.g., chloride ions, etc.) and water molecules may pass along theinterstices of the crystalline structure (columnar grain structure) anddiffuse from the surface of the photocatalyst layer to the glasssubstrate. If such diffused molecules reach the glass substrate, forexample, anions such as chloride ions may react with alkali ions such assodium contained in the glass substrate, producing a water-soluble salt,creating a possibility that the photocatalyst layer may separate fromthe glass substrate together with the undercoat layer, thus causingdefects. Accordingly, there is a problem in durability. As used herein,the “defects” refer to discolored spots or streaks, or separatedportions caused by, for example, the production of the water-solublesalt.

Then, the present inventors obtained further findings described belowand conceived the present invention. More specifically, according to thepresent invention, a photocatalyst layer is formed on an undercoat layerwhich helps the growth of the crystal grains of the photocatalyst,resulting in a suppress of the appearance of the dead layer. Further,the antistripping layer described above formed between the substrate andthe undercoat layer can suppress the separation of the layers from theglass substrate and the occurrence of the defects. Furthermore, bysetting the thickness of the crystalline undercoat layer and thethickness of the photocatalyst layer within the above-described ranges,it is also possible to achieve a low reflectance while achieving acolorless or pale blue reflection color tone, or a bluish green or greenreflection color tone (i.e., fluctuation in reflectance and color toneare suppressed). In the glass member of the present invention, becausethe antistripping layer, the crystalline undercoat layer and thephotocatalyst layer are formed on one surface of a glass substrate, itis possible to produce double paned glass having an improved solar heatgain coefficient as compared to, for example, double paned glassincluding a glass member only having a heat reflecting layer formed onone surface thereof.

As described above, according to the glass member according to the firstembodiment of the present invention, in a single plate including theglass substrate and the heat reflecting layer, the other surface of theglass substrate of the single plate has a combination of a reflectionchromaticity (a*, b*) satisfying −4≦a*≦2 and −5≦b*≦0 and a visible lightreflectance of 10% or less. In this case, the crystalline undercoatlayer has a thickness ranging from 2 to 28 nm, and the photocatalystlayer has a thickness ranging from 2 to 20 nm. By setting thethicknesses of both layers to fall within the above ranges, it ispossible to provide double paned glass, which will be described later,including the glass member of the present invention, in which a visiblelight reflectance at the photocatalyst layer can be controlled withinthe range of 20% or less and a reflection chromaticity (a*, b*) at thephotocatalyst layer can be controlled within the range of −5<a*<0 and−12<b*<0, the double paned glass having both excellent visible lightreflectance and excellent reflection chromaticity.

In the glass member according to the first embodiment of the presentinvention, it is preferable that the crystalline undercoat layer has athickness ranging from 3 to 20 nm and the photocatalyst layer has athickness ranging from 3 to 12 nm. By setting the thicknesses of bothlayers to fall within the above ranges, it is possible to provide doublepaned glass, which will be described later, including the glass memberof the present invention, in which a visible light reflectance at thephotocatalyst layer can be controlled within the range of 17.5% or lessand a reflection chromaticity (a*, b*) at the photocatalyst layer can becontrolled within the range of −5<a*<0 and −8<b*<0, the double panedglass having both further excellent visible light reflectance andfurther excellent reflection chromaticity.

As described previously, according to the glass member according to thesecond embodiment of the present invention, in a single plate includingthe glass substrate and the heat reflecting layer, the other surface ofthe glass substrate of the single plate has a combination of areflection chromaticity (a*, b*) satisfying −15≦a*≦−2 and −10≦b*≦10 anda visible light reflectance of 13% or less. In this case, thecrystalline undercoat layer has a thickness ranging from 2 to 28 nm, andthe photocatalyst layer has a thickness ranging from 2 to 14 nm. Bysetting the thicknesses of both layers to fall within the above ranges,it is possible to provide double paned glass, which will be describedlater, including the glass member of the present invention, whosephotocatalyst layer side surface has a visible light reflectanceadjusted to 20% or less and a reflection chromaticity (a*, b*) adjustedto −12<a*<−2 and −10<b*<5, the double paned glass having both excellentvisible light reflectance and excellent reflection chromaticity.

In the second glass member of present invention, it is preferable thatthe crystalline undercoat layer has a thickness ranging from 3 to 18 nmand the photocatalyst layer has a thickness ranging from 3 to 8 nm. Bysetting the thicknesses of both layers to fall within the above ranges,it is possible to provide double paned glass, which will be describedlater, including the glass member of the present invention, whosephotocatalyst layer side surface has a visible light reflectanceadjusted to 17.5% or less and a reflection chromaticity (a*, b*)adjusted to −9<a*<−3.7 and −10<b*<4, the double paned glass having bothfurther excellent visible light reflectance and further excellentreflection chromaticity.

The visible light reflectance can be measured according to JIS R3106,and the reflection chromaticity can be measured according to JIS Z8729.

In the glass member of the present invention, the thickness of theantistripping layer preferably is, but is not limited to, 2 to 200 nm,and more preferably 5 to 100 nm. When the antistripping layer has athickness of 2 nm or greater, for example, the effect of suppressing thelayer separation and the occurrence of defects can be obtainedsufficiently. When the thickness is 5 nm or greater, water is blocked,and there is suppression (e.g., complete suppression) of the productionof the water soluble salt. When the antistripping layer has a thicknessof 200 nm or less, for example, it is possible to obtain a glass memberalso having the excellent effect of suppressing the layer separation andthe occurrence of defects, while also providing excellent costefficiency. Even when the thickness is 100 nm or less, the effect ofsuppressing the layer separation and the occurrence of defects can beobtained sufficiently. As the antistripping layer, when a layer is usedcontaining silicon dioxide having a refractive index almost equal tothat of the glass substrate, if the thickness is changed within theabove range, the chromaticity hardly changes. When a layer having arefractive index significantly different from that of the glasssubstrate is selected as the antistripping layer, for example, in orderto suppress the change in chromaticity, it is preferable to reduce thethickness of the separation prevention layer to be as small as possible.

In the glass member of the present invention, the glass substrate is notspecifically limited, and any conventionally known glass substrate canbe used. The thickness is usually, but not limited to, 3 to 12 mm. Inthe present invention, as the “glass substrate”, instead of a commonlyused substrate made of glass, a substrate made of resin such aspolycarbonate can be used as long as the properties of the single platesatisfy the above ranges.

As described previously, the antistripping layer of the presentinvention includes at least one selected from the group consisting of anoxide, an oxynitride and a nitride containing at least one of siliconand tin. Specific examples include silicon oxide, silicon oxynitride,silicon nitride, tin oxide, tin oxynitride and tin nitride. Among them,it is preferable to use silicon oxide. Preferably, these materials areamorphous. These materials may be used alone or in a combination of twoor more. When a substrate produced by a float process is used as theglass substrate, the antistripping layer can be a tin modified layer oran amorphous tin oxide layer formed on the contact face between theglass substrate and a tin bath during the production of the substrate.As described previously, the antistripping layer has the function ofblocking ions having a small ionic radius such as chloride ions andwater molecules and hindering them from reaching the glass substratefrom the outside. Accordingly, by forming the antistripping layer on theglass substrate, it is possible to prevent the production of awater-soluble salt due to the ions and water molecules, as well as toprevent the separation of the crystalline undercoat layer from the glasssubstrate caused by the dissolution of the water-soluble salt.

The crystalline undercoat layer of the present invention preferablyincludes, for example, at least one of a crystalline metal oxide and acrystalline metal oxynitride. As the metal oxide, zirconium oxide can beused, for example. As the metal oxynitride, zirconium oxynitride can beused, for example. Particularly, it is preferable that the crystallineundercoat layer includes at least one of zirconium oxide and zirconiumoxynitride. The crystal systems of these metal substances preferably aremonoclinic type. These substances may be used alone or in a combinationof two or more. The crystalline undercoat layer may further include asmall amount of nitrogen, tin, carbon or the like.

The photocatalyst layer of the present invention preferably includes,for example, at least one of a metal oxide and a metal oxynitride.Examples of the metal oxide include titanium oxide and titaniumoxycarbide (TiO_(x)C_(y)). As the metal oxynitride, titanium oxynitrideis used. They may be used alone or in combination of two or more.Particularly, it is preferable that the photocatalyst layer includes atleast one of titanium oxide and titanium oxynitride. The crystal systemsof these substances preferably are, but are not limited to, anatase type(tetragonal system). The photocatalyst layer may further include a smallamount of nitrogen, tin, carbon or the like.

Further, by doping the photocatalyst layer with a metal, it is alsopossible to facilitate the generation of carriers and improve thephotocatalytic effect. As the metal, Zn, Mo, Fe are preferable becausethey have a high photocatalytic-activity-enhancing effect. When Zn or Mois used as the metal, the amount of the metal in the photocatalyst layerpreferably is 0.1 to 1 mass %, and more preferably 0.2 to 0.5 mass %.When Fe is used as the metal, the amount of Fe in the photocatalystlayer preferably is 0.001 to 0.5 mass %. When the amount of the metaladded is not less than the above-described lower limit, the effectproduced by the doping can be provided. When the amount of the metaladded is not greater than the upper limit, the possibility of decreasingthe photocatalytic activity of the photocatalyst layer can be avoidedsufficiently, the possibility of decreasing the photocatalytic activitybeing caused by the disorder of the crystal structure of thephotocatalyst or the formation of recombination center, and both of thedisorder of the crystal structure of the photocatalyst and the formationof recombination center being cause by the presence of the metal.

In the glass member of the present invention, both the crystallineundercoat layer and the photocatalyst layer preferably comprise at leastone of a crystalline metal oxide and a crystalline metal oxynitride.Particularly, it is preferable that at least one of distances betweenoxygens in the crystals contained in the undercoat layer is similar toone of the distances between oxygens in the crystals contained in thephotocatalyst layer. It seems that, by the combination of thecrystalline undercoat layer and the photocatalyst layer for satisfyingthis condition, the oxygen atoms are shared when the photocatalyst layeris formed on the surface of the crystalline undercoat layer, and itmakes it easy for the crystalline photocatalyst layer to growcontinuously, and thus the formation of the dead layer is suppressed. Inrelation to the distance between oxygen atoms, for example, monocliniczirconium oxide and anatase type titanium oxide are similar to eachother in a certain portion (a range from 90 to 110%). Accordingly, whenmonoclinic zirconium oxide is selected as the material of thecrystalline undercoat layer, the crystals of anatase type titanium oxideare easily formed on the surface thereof. As the crystalline undercoatlayer, other than monoclinic zirconium oxide, it is preferable to usedoped zirconium oxide or doped zirconium oxynitride with a small amountof nitrogen, tin, carbon or the like, for example. As the photocatalystlayer, other than anatase type titanium oxide, it is preferable to usedoped titanium oxide or doped titanium oxynitride with a small amount ofnitrogen, tin, carbon or the like, for example.

As for a monoclinic zirconium oxide layer which was mentioned as apreferable undercoat layer, as the electron diffraction image obtainedby irradiating an electron beam from a direction perpendicular (normaldirection) to the cross section of the layer, the diffraction image fromthe (111) plane or the (−111) plane is observed. The spacing of latticeplanes of the (111) orientation is, for example, 0.26 to 0.30 nm, andthe spacing of lattice planes of the (−111) orientation is, for example,0.30 to 0.34 nm. With zirconium oxide whose spacing of lattice planesfalls within this range, it is possible to sufficiently avoid aninfluence on the rapid crystal growth of the photocatalyst layer, theinfluence resulting from mismatching of lattice alignment of oxygenatoms on the oxide (e.g., titanium oxide, etc.) forming thephotocatalyst layer, when there is displacement of oxygen atoms in thecrystal plane due to a distortion in the crystal.

As for an anatase type titanium oxide layer which was mentioned as apreferable photocatalyst layer, as the electron diffraction imageobtained by irradiating an electron beam from a direction perpendicular(normal direction) to the cross section of the layer, the diffractionimage from the (101) plane is observed. The spacing of lattice planes ofthe (101) orientation is, for example, 0.33 to 0.37 nm. With titaniumoxide whose spacing of lattice planes falls within this range, it ispossible to sufficiently avoid an influence on the rapid crystal growthof the photocatalyst layer, the influence resulting from mismatching oflattice alignment of oxygen atoms on the oxide forming the crystallineundercoat layer, when there is displacement of oxygen atoms in thecrystal plane due to a distortion in the crystal.

In the present invention, a low emissivity film is used as the heatreflecting layer, for example. The low emissivity film preferably is,but is not limited to, a multilayer laminate including a dielectric,silver, a dielectric, silver and a dielectric are laminated in thisorder (a constitution comprising a substrate/a first dielectric layer/afirst silver layer/a second dielectric layer/a second silver layer/athird dielectric layer) formed by a well-known film forming method suchas sputtering method. As the dielectrics, titanium oxide, zinc oxide,tin oxide, niobium oxide, tantalum oxide, silicon nitride, siliconoxynitride and the like can be used. The heat reflecting layerpreferably has, but not limited to, a thickness of 110 to 230 nm, andmore preferably 125 to 200 nm. Those skilled in the art can set thereflection chromaticity and visible light reflectance of the singleplate as appropriate according to, for example, the thickness, materialand layer structure of the heat reflecting layer.

As the method for producing the glass member of the present invention,for example, the following method can be used, but is not limitedthereto. First, an antistripping layer is formed on one surface of aglass substrate. Subsequently, a crystalline undercoat layer is formedon the surface of the antistripping layer, after which a photocatalystlayer is formed on the surface of the crystalline undercoat layer. Onthe other surface of the glass substrate, a heat reflecting layer isformed.

As the method for forming the antistripping layer, any conventionallyknown method can be used such as sputtering method or vacuum depositionmethod.

As the method for forming the crystalline undercoat layer, anyconventionally known method can be used such as a liquid phase method(e.g., sol-gel method, liquid phase precipitation method, etc.) or avapor phase method (e.g., sputtering method, vacuum deposition method,CVD method, etc.). By using these methods, a crystallinity-enhancingeffect of the photocatalyst layer produced by the crystalline undercoatlayer can be obtained. Particularly, it is preferable to use a vaporphase method because an excellent crystal-growth effect can be obtained.The method for forming the photocatalyst layer is not specificallylimited, either, and any one of those listed for the method for formingthe crystalline undercoat layer can be used. Particularly, it ispreferable to use the vapor phase method.

The method for forming the heat reflecting layer is not specificallylimited, and any conventionally known method can be used such assputtering method.

The thicknesses of the glass substrate, antistripping layer, crystallineundercoat layer, photocatalyst layer and heat reflecting layer of thepresent invention can be controlled by conventionally known methods.

An example of the double paned glass of the present invention will bedescribed with reference to FIG. 2. As long as the double paned glass ofthe present invention includes the glass member of the presentinvention, there is no other limitation on the constitution.

FIG. 2 is a cross sectional view showing an example of double panedglass of the present invention. The same reference numbers are given tothe same components of FIG. 1. In double paned glass 50, a glass plate20 and a glass member 30 are placed with a spacer 40 placed therebetweenso as to create a space between the facing surfaces of the glass plate20 and the glass member 30. The glass member 30 is placed such that itsphotocatalyst layer 3 serves as one of the outermost layers of thedouble paned glass 50. In this diagram, a heat reflecting layer 24 is alow emissivity film comprising a dielectric 5 a/silver 6 a/a dielectric5 b/silver 6 b/a dielectric 5 c, but that constitution is not limiting.Such double paned glass 50 is usually installed such that the surfacehaving the glass member 30 thereon (specifically, the surface of thephotocatalyst layer 3) faces the outdoor side and another glass plate 20faces the indoor side.

In the double paned glass of the present invention, there is no specificlimitation on another glass plate different from the glass member of thepresent invention (hereinafter referred to as an “indoor side glassplate”), and any one of the glass plates listed above can be used. Thethickness is not specifically limited, either, and the indoor side glassplate can have a thickness described above. The spacer is notspecifically limited, either, and any conventionally known spacer can beused. The space between the glass member and the indoor side glass platecreated by the spacer may be a hollow cavity or it may be filled with amaterial.

In the double paned glass of the present invention, the distance of thespace between the glass member and the indoor side glass platepreferably is, but is not limited to, 6 to 18 mm.

The method for producing the double paned glass including the glassmember of the present invention is not specifically limited, and anyconventionally known method can be used.

EXAMPLE 1

According to the following method, a glass member as shown in FIG. 1 wasproduced, and using the glass member, double paned glass as shown inFIG. 2 was produced.

(Method for Producing Double Paned Glass)

A heat reflecting layer 24 was formed on one surface of a glasssubstrate 10 (length: 10 cm, width: 10 cm, thickness: 3 mm). As the heatreflecting layer 24, a low emissivity film (Low-E film; thickness: 161nm) comprising a dielectric 5 a/silver 6 a/a dielectric 5 b/silver 6 b/adielectric 5 c was formed such that, in a single plate comprising theglass plate 10 and the heat reflecting layer 24, the glass substrateside surface had the following optical properties: a reflectionchromaticity (a*, b*) satisfying −4≦a*≦2 and −5≦b*≦0 and a visible lightreflectance of 10% or less.

The specific constitution of the heat reflecting layer 24 was asfollows: a glass substrate/zinc oxide (16.1 nm)/silver (9.7 nm)/titaniumoxide (2.6 nm)/zinc oxide (23.3 nm)/silicon nitride (10.2 nm)/zinc oxide(12.7 nm)/silicon nitride (9.4 nm)/zinc oxide (22.3 nm)/silver (12.0nm)/titanium oxide (2.6 nm)/zinc oxide (29.9 nm)/silicon nitride (10.4nm).

Each layer of the heat reflecting layer 24 was formed by the followingmethod. The titanium oxide layers and the zinc oxide layers were formedby a reactive sputtering method using titanium and zinc, respectively,as a metal target and a mixed gas of an argon gas and an oxygen gas as adischarge gas. The silicon nitride layers were formed by a reactivesputtering method using a Si target and a mixed gas of an argon gas anda nitrogen gas as a discharge gas. The silver layers were formed by asputtering method using a silver target and an argon gas as a dischargegas. As the discharge power source, a direct current pulse power sourcewas used.

The optical properties of the single plate comprising the glasssubstrate 10 and the heat reflecting layer 24 were measured, and theresults were as follows.

Reflection chromaticity viewing from glass substrate 10 side (a*,b*)=(−0.21, −3.63)

Visible light reflectance viewing from glass substrate 10 side 5.6%

Reflection chromaticity viewing from heat reflecting layer 24 side (a*,b*)=(−3.81, 3.54)

Visible light reflectance viewing from heat reflecting layer 24 side4.4%

On the other surface of the glass substrate 10, an amorphous siliconoxide (SiO₂) layer was formed as an antistripping layer 1 by reactivesputtering method. Subsequently, on the surface of the antistrippinglayer 1, a monoclinic zirconium oxide (ZrO₂) layer was formed as acrystalline undercoat layer 2 by a reactive sputtering method. On thesurface of the crystalline undercoat layer 2, an anatase type titaniumoxide (TiO₂) layer was formed as a photocatalyst layer 3 by a sputteringmethod. Thereby, a glass member 30 was produced.

The obtained glass member 30 and an indoor side glass plate 20(thickness: 3 mm) were placed with a spacer (thickness: 12 mm) placedtherebetween so as to create a space between the facing surfaces of theglass member 30 and the indoor side glass plate 20. Thereby, doublepaned glass 50 was produced.

(Changing of Thickness of Photocatalyst Layer)

Double paned glasses were produced in the same method as describedabove, except that the thickness of the photocatalyst layer was changedat a pitch of 2 nm, the thickness of the antistripping layer 1 (SiO₂layer) was set to 10 nm and the thickness of the crystalline undercoatlayer 2 (ZrO₂ layer) was set to 5 nm.

(Changing of Thickness of Crystalline Undercoat Layer)

Double paned glasses were produced in the same method as describedabove, except that the thickness of the crystalline undercoat layer waschanged at a pitch of 2 nm, the thickness of the antistripping layer 1(SiO₂ layer) was set to 10 nm and the thickness of the photocatalystlayer 3 (TiO₂ layer) was set to 5 nm.

(Measurement of Visible Light Reflectance)

For each of the double paned glass 50 obtained in the manner describedabove, the visible light reflectance (R %) of the photocatalyst layer 3side surface was measured according to JIS R3106. The results are shownin FIGS. 3 and 4. FIG. 3 is a graph showing the thickness of thephotocatalyst layer 3 versus the visible light reflectance. FIG. 4 is agraph showing the thickness of the crystalline undercoat layer 2 versusthe visible light reflectance. The results indicate that the visiblelight reflectance was high when the photocatalyst layer 3 and thecrystalline undercoat layer 2 each had a thickness within a range of 40to 60 nm, and the visible light reflectance was low when the thicknesswas out of this range. The visible light reflectance (R %) preferably is20% or less, and more preferably 17.5% or less.

(Measurement of Reflection Chromaticity of Double Paned Glass)

For the double paned glasses obtained in the manner described above,changes in the reflection chromaticity (a*, b*) of the photocatalystlayer 3 side surface were measured. The reflection chromaticity wascalculated according to JIS Z8729 using a spectrum obtained by aspectrophotometer.

The results of the obtained reflection chromaticity (a*, b*) are shownin FIGS. 5 to 8. FIGS. 5 and 6 are graphs showing the reflectionchromaticity (a*, b*) of the double paned glass having variousphotocatalyst layer thickness. In FIG. 5, based on the results of FIG.3, a range indicating a visible light reflectance of 20% or less issurrounded by a rectangular frame, and in FIG. 6, based on the resultsof FIG. 3, a range indicating a visible light reflectance of 17.5% orless is surrounded by a rectangular frame. FIGS. 7 and 8 are graphsshowing the reflection chromaticity (a*, b*) of the double paned glasseshaving various crystalline undercoat layer thickness. In FIG. 7, basedon the results of FIG. 4, a range indicating a visible light reflectanceof 20% or less is surrounded by a rectangular frame, and in FIG. 8,based on the results of FIG. 4, a range indicating a visible lightreflectance of 17.5% or less is surrounded by a rectangular frame.

(Measurement of Photocatalystic Activity)

For the double paned glass 50 obtained in the manner described above,evaluations were made in terms of photocatalytic activity by thefollowing method. First, UV irradiation was performed for 60 minutesunder the conditions that a black lamp (center wavelength: 365 nm) wasused as a light source and the luminance was set to 1 mW/cm², and thenthe contact angle (θ) of water was measured. More specifically, a UVlight was irradiated to the photocatalyst layer side surface of thedouble paned glass under the above conditions. Thereafter, the doublepaned glass was placed on a horizontal table such that the surface ofthe photocatalyst layer was horizontal, and 0.4 μL of water was droppedto the surface of the photocatalyst layer. Then, the contact angle ofthe water droplet on the surface was measured using a contact anglemeter (CA-150 available from Kyowa Interface Science Co., Ltd.). For thedouble paned glass that exhibited a contact angle (θ) of not greaterthan 15 degrees and not greater than 20 degrees, the thickness of thecrystalline undercoat layer 2 and that of the photocatalyst layer 3 weredetermined.

The above measurement results are shown in Table 1 given below. In Table1 given below, the reflection chromaticity −5<a*<0, −12<b*<0 is a rangewhere a pale blue reflection color is observed, and the reflectionchromaticity −5<a*<0, −8<b*<0 is a range where light pale bluereflection color is observed. TABLE 1 Thickness of crystalline Thicknessof undercoat photocatalyst layer 2 layer 3 Reflection (1) −5 < a* < 0 0to 58 nm 0 to 56 nm chromaticity −12 < b* < 0 (a*, b*) (2) −5 < a* < 0 0to 58 nm 0 to 12 nm −8 < b* < 0 Visible light (3) Not greater than 20% 0to 28 nm 0 to 20 nm reflectance (4) Not greater than 17.5% 0 to 20 nm 0to 16 nm (R) Contact angle (5) Not greater than 20 Not less Not less ofwater degrees than 2 nm than 2 nm (θ) (6) Not greater than 15 Not lessNot less degrees than 3 nm than 3 nm Range satisfying (1), (3) and (5) 2to 28 nm 2 to 20 nm (Preferable range) Range satisfying (2), (4) and (6)3 to 20 nm 3 to 12 nm (More preferable range)

The results of Table 1 given above indicate that, in this example,double paned glass having excellent photocatalytic activity whileachieving both excellent visible light reflectance and excellentreflection chromaticity is obtained by setting the thickness of thecrystalline undercoat layer 2 in the range of 2 to 28 nm and thethickness of the photocatalyst layer 3 in the range of 2 to 20 nm.Further, they indicate that, by setting the thickness of the crystallineundercoat layer 2 in the range of 3 to 20 nm and the thickness of thephotocatalyst layer 3 in the range of 3 to 12 nm, further excellentphotocatalytic activity, further excellent visible light reflectance,and a colorless or pale blue reflection color tone can be also achieved.

EXAMPLE 2

A glass member 30 having a structure similar to that of Example 1 wasproduced in the same manner as in Example 1 except that the specificfilm constitution of the heat reflecting layer 24 was changed. Using theproduced glass member 30, double paned glass 50 similar to that of FIG.2 was produced.

(Method for Producing Double Paned Glass)

In the same manner as in Example 1, a heat reflecting layer 24 wasproduced on one surface of a glass substrate 10. The optical propertiesof a single plate comprising the glass substrate 10 and the heatreflecting layer 24 were set such that the glass substrate side surfacehad a reflection chromaticity (a*, b*) satisfying −15≦a*≦−2 and−10≦b*≦10 and a visible light reflectance of 13% or less. The thicknessof the low emissivity film was set to 148 mm.

The specific constitution of the heat reflecting layer 24 was asfollows: a glass substrate/zinc oxide (17.2 nm)/silver (7.7 nm)/titaniumoxide (3.4 nm)/zinc oxide (20.4 nm)/silicon nitride (8.1 nm)/zinc oxide(16.4 nm)/silicon nitride (12.3 nm)/zinc oxide (21.9 nm)/silver (11.3nm)/titanium oxide (2.9 nm)/zinc oxide (20.2 nm)/silicon nitride (8.6nm).

The optical properties of the single plate comprising the glasssubstrate 10 and the heat reflecting layer 24 were measured, and theresults were as follows.

Reflection chromaticity viewing from glass substrate 10 side (a*,b*)=(−7.69, 7.12)

Visible light reflectance viewing from glass substrate 10 side 9.0%

Reflection chromaticity viewing from heat reflecting layer 24 side (a*,b*)=(−11.2, 18.6)

Visible light reflectance viewing from heat reflecting layer 24 side8.9%

Similarly to Example 1, double paned glass was produced by changing thethickness of the photocatalyst layer and that of the crystallineundercoat layer, and the visible light reflectance and reflectionchromaticity of the photocatalyst layer 3 side surface were measured inthe same manner as in Example 1. The photocatalytic activity was alsomeasured in the same manner as in Example 1.

The measurement results of the measured photocatalyst layer 3 sidevisible light reflectance are shown in FIGS. 9 and 10. FIG. 9 is a graphshowing the thickness of the photocatalyst layer 3 versus the visiblelight reflectance. FIG. 10 is a graph showing the thickness of thecrystalline undercoat layer 2 and the visible light reflectance. Theresults indicate that the visible light reflectance was high when thephotocatalyst layer 3 and the crystalline undercoat layer 2 each had athickness within a range of 40 to 60 nm, and the visible lightreflectance was low when the thickness was out of this range. Thevisible light reflectance (R %) preferably is 20% or less, and morepreferably 17.5% or less.

The measurement results of the photocatalyst layer 3 side reflectionchromaticity (a*, b*) measured in the same manner as in Example 1 areshown in FIGS. 11 to 14. FIGS. 11 and 12 are graphs showing thereflection chromaticity (a*, b*) of the double paned glass havingvarious photocatalyst layer thickness. In FIG. 11, based on the resultsof FIG. 9, a range indicating a visible light reflectance of 20% or lessis surrounded by a rectangular frame, and in FIG. 12, based on theresults of FIG. 9, a range indicating a visible light reflectance of17.5% or less is surrounded by a rectangular frame. FIGS. 13 and 14 aregraphs showing the reflection chromaticity (a*, b*) of the double panedglass having various crystalline undercoat layer thickness. In FIG. 13,based on the results of FIG. 10, a range indicating a visible lightreflectance of 20% or less is surrounded by a rectangular frame, and inFIG. 14, based on the results of FIG. 10, a range indicating a visiblelight reflectance of 17.5% or less is surrounded by a rectangular frame.

The above measurement results are shown in Table 2 given below. Thereflection color tone of the double paned glass of this examplepreferably is from bluish green to green. Particularly preferable rangeof reflection color tone is −12<a*<−2, −10<b*<5, and more preferablerange of reflection color tone is −9<a*<−3.7, −10<b*<4. TABLE 2Thickness of crystalline Thickness of undercoat photocatalyst layer 2layer 3 Reflection (1) −12 < a* < −2 0 to 68 nm 0 to 56 nm chromaticity−10 < b* < 4 (a*, b*) (2) −9 < a* < −3.7 0 to 66 nm 0 to 16 nm −10 < b*< 4 Visible light (3) Not greater than 20% 0 to 28 nm 0 to 14 nmreflectance (4) Not greater than 17.5% 0 to 18 nm 0 to 8 nm (R) Contactangle (5) Not greater than 20 Not less Not less of water degrees than 2nm than 2 nm (θ) (6) Not greater than 15 Not less Not less degrees than3 nm than 3 nm Range satisfying (1), (3) and (5) 2 to 28 nm 2 to 14 nm(Preferable range) Range satisfying (2), (4) and (6) 3 to 18 nm 3 to 8nm (More preferable range)

The results of Table 2 given above indicate that, in this example,double paned glass having excellent photocatalytic activity whileachieving both excellent visible light reflectance and excellentreflection chromaticity is obtained by setting the thickness of thecrystalline undercoat layer 2 in the range of 2 to 28 nm and thethickness of the photocatalyst layer 3 in the range of 2 to 14 nm.Further, they indicate that, by setting the thickness of the crystallineundercoat layer 2 in the range of 3 to 18 nm and the thickness of thephotocatalyst layer 3 in the range of 3 to 8 nm, further excellentphotocatalytic activity, further excellent visible light reflectance,and a bluish green or green reflection color tone can also be achieved.

EXAMPLE 3

Double paned glass 50 was produced in the same manner as in Example 1except that the thicknesses of the antistripping layer 1, thecrystalline undercoat layer 2 and the photocatalyst layer 3 were set to10 nm, 5 nm and 5 nm, respectively. Then, this double paned glass wassubjected to measurement for chromaticity of transmitted light(transmission chromaticity), reflection chromaticity (of thephotocatalyst layer 3 side surface and the indoor side glass plate 20side surface), visible light transmittance, visible light reflectance,solar transmittance and solar heat gain coefficient. The visible lightreflectance, transmission chromaticity and reflection chromaticity weremeasured in the same manner as in Example 1. The visible lighttransmittance and solar transmittance were measured according to JISR3106. The solar heat gain coefficient was calculated according to JISR3106 using a spectrum obtained by a spectrophotometer.

EXAMPLE 4

Double paned glass was produced and measured in the same manner as inExample 3 except that the thickness of the antistripping layer 1, thecrystalline undercoat layer 2 and the photocatalyst layer 3 were set to10 nm, 10 nm and 5 nm, respectively.

EXAMPLE 5

Double paned glass was produced and measured in the same manner as inExample 3 except that the thickness of the antistripping layer 1, thecrystalline undercoat layer 2 and the photocatalyst layer 3 were set to10 nm.

COMPARATIVE EXAMPLE 1

Double paned glass was produced in the same manner as in Example 1except that an antistripping layer, a crystalline undercoat layer and aphotocatalyst layer were not formed and only a heat reflecting layer waslaminated on a glass substrate. Then, the double paned glass wassubjected to the same measurements as in Example 5.

The measurement results of Examples 3 to 5 and Comparative Example 1 areshown in Table 3 given below. TABLE 3 Reflection chromaticityPhotocatalyst layer side Glass plate side Visible light Transmissionchromaticity (Outdoor side) (Indoor side) transmittance a* b* a* b* a*b* (%) Ex. 3 −2.80 3.25 −1.07 −3.78 −2.31 −0.27 71.1 Ex. 4 −2.77 3.72−1.04 −5.14 −2.48 −1.12 70.0 Ex. 5 −2.74 4.74 −0.89 −7.55 −2.68 −2.7368.1 Comp. −2.77 2.63 −1.36 −1.47 −2.30 1.12 72.1 Ex. 1 Visible lightreflectance (%) Photocatalyst Solar transmittance Solar heat gain layerside Glass plate side (%) coefficient (%) (Outdoor side) (Indoor side)(300 to 2500 nm) Summer Winter Ex. 3 12.0 12.6 37.6 41.4 40.9 Ex. 4 13.413.5 37.0 40.8 40.3 Ex. 5 15.8 15.1 35.5 39.2 38.7 Comp. 10.8 11.8 38.242.1 41.7 Ex. 1

The results of Table 3 indicate that the solar heat gain coefficient isincreased by forming an antistripping layer 1, a crystalline undercoatlayer 2 and a photocatalyst layer 3 on the other surface of a glasssubstrate only having a heat reflecting layer thereon. The smaller thevalue of solar heat gain coefficient, the greater the ability to reducethe amount of heat of sunlight transferred indoors, and effects such asan improvement in cooling efficiency in the summer can be obtained.

EXAMPLE 6

Double paned glass was produced in the same manner as in Example 3except that each of the heat reflecting layers listed in Table 4 givenbelow was laminated on a glass substrate, and the thicknesses of theantistripping layer 1, the crystalline undercoat layer 2 and thephotocatalyst layer 3 were set to 10 nm, 10 nm and 5 nm, respectively.Then, the optical properties of the double paned glass was measured inthe same manner as in Example 3.

Each heat reflecting layer was formed by forming a first dielectriclayer, a first silver layer, a second dielectric layer, a second silverlayer and a third dielectric layer on a surface of a glass substrate.Table 4 shows the materials of the layers forming each heat reflectinglayer. Table 5 shows the thicknesses of the layers forming each heatreflecting layer. Table 6 shows the optical thicknesses at a wavelengthof 530 nm of the dielectric layers and the silver layers. The thicknessof Table 5 is a physical thickness obtained by measuring the crosssection of a layer using a transmission electron microscope (EM002Btransmission electron microscope available from TOPCON CORPORATION). Theoptical thickness of Table 6 is a value obtained by multiplying thephysical thickness by a refractive index at 530 nm. The refractive indexwas determined from the measurement results obtained using a spectralellipsometer (VASE system available from J. A. Woollam Co., Inc., theUnited States). TABLE 4 First First dielectric silver Second layer layersilver layer material material Second dielectric layer material materialThird dielectric layer material Sample 6 Zinc oxide Silver Niobium Tindoped Silicon Tin doped Silicon Zinc oxide Silver Niobium Tin dopedSilicon oxide zinc oxide nitride zinc oxide nitride oxide zinc oxidenitride Sample 7 Zinc oxide Silver Titanium Zinc oxide Silicon Zincoxide Silicon Zinc oxide Silver Titanium Zinc oxide Silicon oxidenitride nitride oxide nitride Sample 8 Zinc oxide Silver Titanium Zincoxide Silicon Zinc oxide Silicon Zinc oxide Silver Titanium Zinc oxideSilicon oxide nitride nitride oxide nitride Sample 9 Zinc oxide SilverNiobium Tin doped Silicon Tin doped Silicon Zinc oxide Silver NiobiumTin doped Silicon oxide zinc oxide nitride zinc oxide nitride oxide zincoxide nitride Sample 10 Zinc oxide Silver Niobium Zinc oxide SiliconZinc oxide Silicon Zinc oxide Silver Titanium Tin doped Silicon oxidenitride nitride oxide zinc oxide nitride Sample 11 Zinc oxide SilverNiobium Tin doped Silicon Tin doped Silicon Zinc oxide Silver NiobiumTin doped Silicon oxide zinc oxide nitride zinc oxide nitride oxide zincoxide nitride Sample 12 Zinc oxide Silver Titanium Tin doped SiliconTitanium Silicon Zinc oxide Silver Niobium Tin doped Silicon oxide zincoxide nitride oxide nitride oxide zinc oxide nitride Sample 13 Zincoxide Silver Titanium Zinc oxide Silicon Zinc oxide Silicon Zinc oxideSilver Titanium Zinc oxide Silicon oxide nitride nitride oxide nitrideSample 14 Zinc oxide Silver Niobium Tin doped Silicon Tin doped SiliconZinc oxide Silver Niobium Tin doped Silicon oxide zinc oxide nitridezinc oxide nitride oxide zinc oxide nitride Sample 15 Zinc oxide SilverTitanium Zinc oxide Silicon Zinc oxide Silicon Zinc oxide SilverTitanium Zinc oxide Silicon oxide nitride nitride oxide nitride Sample16 Zinc oxide Silver Titanium Zinc oxide Silicon Zinc oxide Silicon Zincoxide Silver Titanium Zinc oxide Silicon oxide nitride nitride oxidenitride Sample 17 Zinc oxide Silver Titanium Tin doped Silicon Tin dopedSilicon Zinc oxide Silver Titanium Tin doped Silicon oxide zinc oxidenitride zinc oxide nitride oxide zinc oxide nitride Sample 18 Zinc oxideSilver Niobium Tin doped Silicon Tin doped Silicon Zinc oxide SilverNiobium Tin doped Silicon oxide zinc oxide nitride zinc oxide nitrideoxide zinc oxide nitride Sample 19 Zinc oxide Silver Titanium Zinc oxideSilicon Zinc oxide Silicon Zinc oxide Silver Titanium Zinc oxide Siliconoxide nitride nitride oxide nitride Sample 20 Zinc oxide Silver TitaniumZinc oxide Silicon Zinc oxide Silicon Zinc oxide Silver Titanium Zincoxide Silicon oxide nitride nitride oxide nitride

TABLE 5 First dielectric First silver Second layer layer silver layerthickness thickness thickness (nm) (nm) Second dielectric layerthickness (nm) (nm) Third dielectric layer thickness (nm) Sample 6 23.27.7 4.0 21.3 8.8 18.5 12.8 22.6 11.3 3.7 18.8 9.5 Sample 7 20.9 7.7 3.521.0 8.2 18.1 12.4 22.2 11.3 3.7 19.1 9.2 Sample 8 14.2 7.7 4.0 19.2 7.514.9 10.6 20.7 11.3 2.0 23.9 9.6 Sample 9 10.8 7.7 4.0 20.3 7.1 15.611.3 21.8 11.3 2.0 25.3 8.0 Sample 10 10.8 7.7 4.0 21.4 7.1 15.5 11.321.8 11.3 2.0 25.3 8.0 Sample 11 12.1 7.7 2.8 18.3 7.3 9.3 9.5 20.3 11.32.0 15.8 8.1 Sample 12 12.1 7.7 4.0 18.3 7.3 4.7 9.5 20.3 11.3 2.0 15.88.1 Sample 13 11.1 7.7 2.7 18.2 7.6 7.4 9.6 20.6 11.3 2.1 15.4 8.3Sample 14 20.2 7.7 3.4 20.4 8.0 15.3 12.0 21.8 11.3 3.7 17.3 8.5 Sample15 17.1 7.7 2.7 20.1 7.5 16.0 11.7 21.4 11.3 3.4 18.6 8.1 Sample 16 16.27.7 3.4 20.5 8.1 16.5 12.3 22.0 11.3 2.9 20.7 8.7 Sample 17 16.2 7.7 3.420.8 8.1 16.7 12.3 22.0 11.3 2.9 20.9 8.7 Sample 18 16.2 7.7 3.6 20.88.1 16.7 12.3 22.0 11.3 3.0 20.9 8.7 Sample 19 28.3 10.9 4.0 19.3 8.42.1 8.7 20.9 8.5 1.7 21.0 9.0 Sample 20 12.4 9.7 4.0 20.8 8.0 19.1 12.122.2 12.0 2.0 25.5 9.8

TABLE 6 First dielectric layer First silver layer Second dielectriclayer Second silver layer Third dielectric layer optical thickness (nm)optical thickness (nm) optical thickness (nm) optical thickness (nm)optical thickness (nm) Sample 6 46.4 1.1 177.2 1.6 65.1 Sample 7 41.71.1 173.5 1.6 66.1 Sample 8 28.4 1.1 156.1 1.6 72.2 Sample 9 21.5 1.1161.4 1.6 71.1 Sample 10 21.5 1.1 164.3 1.6 71.3 Sample 11 24.2 1.1135.9 1.6 52.3 Sample 12 24.2 1.1 132.1 1.6 52.3 Sample 13 22.3 1.1134.3 1.6 52.8 Sample 14 40.4 1.1 162.8 1.6 60.1 Sample 15 34.1 1.1160.5 1.6 62.0 Sample 16 32.4 1.1 168.0 1.6 66.1 Sample 17 32.4 1.1168.0 1.6 66.1 Sample 18 32.4 1.1 168.0 1.6 66.1 Sample 19 56.5 1.5129.0 1.2 64.5 Sample 20 24.8 1.4 174.8 1.7 75.8

The measurement results of the reflection chromaticity of the glasssubstrate side of the single plate, the transmission chromaticity of thedouble paned glass, the reflection chromaticity of the indoor sidesurface of the double paned glass and that of the outdoor side surfaceof the same are shown in Table 7. Likewise, the measurement results ofthe visible light reflectance of the glass substrate side of the singleplate, the visible light transmittance of the double paned glass, thevisible light reflectance of the indoor side surface of the double panedglass and that of the outdoor side surface of the same are shown inTable 8. TABLE 7 Single plate (glass surface side) Double paned glassDouble paned glass (outdoor side) Double paned glass (indoor side)Reflected light chromaticity Transmitted light chromaticity Reflectedlight chromaticity Reflected light chromaticity a* b* a* b* a* b* a* b*Sample 6 −5.0 9.2 −2.1 −0.3 −3.7 1.6 −4.0 7.2 Sample 7 −5.0 9.2 −2.0 0.2−3.7 1.8 −4.9 7.0 Sample 8 −3.2 0.0 −2.6 1.5 −2.6 −3.5 −4.9 1.0 Sample 9−3.9 −1.8 −2.4 1.2 −3.1 −4.5 −5.7 1.8 Sample 10 −3.8 −1.2 −2.4 1.5 −3.0−4.0 −5.9 2.9 Sample 11 −12.0 −5.0 −1.9 0.7 −7.7 −6.7 −6.6 −3.9 Sample12 −12.2 −6.3 −1.8 0.9 −7.8 −7.4 −6.9 −4.4 Sample 13 −12.0 −5.0 −1.3 1.3−8.9 −5.5 −8.2 −3.6 Sample 14 −12.0 9.2 −1.3 −0.5 −7.9 1.4 −7.7 5.8Sample 15 −12.0 9.2 −1.1 0.1 −7.7 1.6 −8.6 5.4 Sample 16 −7.7 7.1 −1.80.9 −5.2 0.7 −6.5 6.2 Sample 17 −7.0 4.9 −1.9 0.1 −5.0 −0.6 −6.1 5.5Sample 18 −7.3 4.7 −1.8 0.2 −5.1 −0.7 −6.3 5.5 Sample 19 −7.4 7.3 −1.81.1 −5.2 1.3 −6.3 −4.6 Sample 20 0.3 −4.7 −3.1 2.4 −0.6 −5.6 −4.5 1.2

TABLE 8 Single plate Double paned Double paned (glass Double paned glassglass surface side) glass (outdoor side) (indoor side) Visible lightVisible light Visible light Visible light reflectance transmittancereflectance reflectance (%) (%) (%) (%) Sample 9.3 65.2 15.7 16.5 6Sample 9.2 68.2 15.9 16.8 7 Sample 7.0 69.8 14.1 14.4 8 Sample 8.3 65.714.7 15.0 9 Sample 7.8 67.7 14.5 15.4 10 Sample 7.3 65.9 13.8 15.0 11Sample 7.5 66.5 14.1 15.4 12 Sample 7.3 68.1 14.6 15.7 13 Sample 9.065.3 15.4 16.5 14 Sample 9.0 68.0 15.8 16.7 15 Sample 9.0 67.6 15.7 16.516 Sample 9.2 65.2 15.6 16.2 17 Sample 9.3 65.2 15.6 16.2 18 Sample 10.566.7 17.0 15.7 19 Sample 10.0 66.8 16.9 16.8 20

The results of Tables 7 and 8 given above indicate that even when thedielectric layers are made of different materials, as long as thereflection chromaticity of the single plate and the value of the glasssurface side visible light reflectance fall within the above ranges, itis possible to obtain double paned glass achieving both excellentvisible light reflectance and excellent reflection chromaticity. Theyalso indicate that, by keeping the optical thickness of each dielectriclayer substantially constant, even when part of dielectric material isreplaced by other dielectric material(s), no significant change occursin the reflection chromaticity and visible light reflectance of thesingle plate. When the dielectric material is replaced, for example, byadjusting the physical thickness of each dielectric layer, it ispossible to obtain similar optical properties.

INDUSTRIAL APPLICABILITY

As described above, according to the glass member of the presentinvention, it is possible to realize a low reflectance while achieving acolorless or pale blue reflection color tone or a bluish green or greenreflection color tone, as well as to obtain excellent photocatalyticactivity. Thus, according to the double paned glass including the glassmember of the present invention, it is possible to achieve highphotocatalytic activity while achieving excellent reflectance andreflection color tone in the photocatalyst layer side surface.Therefore, it is suitable for use as double paned glass for largeconstruction use that requires excellent photocatalytic function and aclear appearance.

1. A glass member in which a heat reflecting layer is laminated on onesurface of a glass substrate and a photocatalyst layer is laminated onthe other surface thereof, wherein the glass substrate and the heatreflecting layer are combined such that, in a state in which the heatreflecting layer is laminated on one surface of the glass substrate andthe photocatalyst layer is not laminated on the other surface of theglass substrate, the other surface of the glass substrate has areflection chromaticity (a*, b*) satisfying 4≦a*≦2 and −5≦b*≦0 and avisible light reflectance of 10% or less, an antistripping layer, acrystalline undercoat layer and the photocatalyst layer are laminated inthis order on the other surface of the glass substrate, the crystallineundercoat layer has a thickness ranging from 2 to 28 nm and thephotocatalyst layer has a thickness ranging from 2 to 20 nm, and theantistripping layer comprises at least one material selected from thegroup consisting of an oxide, an oxynitride and a nitride containing atleast one of silicon and tin.
 2. The glass member according to claim 1,wherein the crystalline undercoat layer has a thickness ranging from 3to 20 nm, and the photocatalyst layer has a thickness ranging from 3 to12 nm.
 3. A glass member in which a heat reflecting layer is laminatedon one surface of a glass substrate and a photocatalyst layer islaminated on the other surface thereof, wherein the glass substrate andthe heat reflecting layer are combined such that, in a state in whichthe heat reflecting layer is laminated on one surface of the glasssubstrate and the photocatalyst layer is not laminated on the othersurface of the glass substrate, the other surface of the glass substratehas a reflection chromaticity (a*, b*) satisfying −15≦a*≦−2 and−10≦b*≦10 and a visible light reflectance of 13% or less, anantistripping layer, a crystalline undercoat layer and the photocatalystlayer are laminated in this order on the other surface of the glasssubstrate, the crystalline undercoat layer has a thickness ranging from2 to 28 nm, and the photocatalyst layer has a thickness ranging from 2to 14 nm, and the antistripping layer comprises at least one materialselected from the group consisting of an oxide, an oxynitride and anitride containing at least one of silicon and tin.
 4. The glass memberaccording to claim 3, wherein the crystalline undercoat layer has athickness ranging from 3 to 18 nm, and the photocatalyst layer has athickness ranging from 3 to 8 nm.
 5. The glass member according to claim1 or 3, wherein the antistripping layer comprises at least one materialselected from the group consisting of an amorphous oxide, an amorphousoxynitride and an amorphous nitride containing at least one of siliconand tin.
 6. The glass member according to claim 1 or 3, wherein theantistripping layer comprises silicon oxide.
 7. The glass memberaccording to claim 1 or 3, wherein the crystalline undercoat layercomprises at least one of a metal oxide and a metal oxynitride.
 8. Theglass member according to claim 7, wherein the crystalline undercoatlayer comprises at least one of zirconium oxide and zirconiumoxynitride.
 9. The glass member according to claim 8, wherein thezirconium oxide is monoclinic zirconium oxide.
 10. The glass memberaccording to claim 1 or 3, wherein the photocatalyst layer comprises atleast one of a metal oxide and a metal oxynitride.
 11. The glass memberaccording to claim 10, wherein the photocatalyst layer comprises atleast one of a crystalline metal oxide and a crystalline metaloxynitride.
 12. The glass member according to claim 10, wherein thephotocatalyst layer comprises at least one of titanium oxide andtitanium oxynitride.
 13. The glass member according to claim 12, whereinthe titanium oxide is anatase type titanium oxide.
 14. The glass memberaccording to claim 1 or 3, wherein the heat reflecting layer is amultilayer laminate (a dielectric/Ag/a dielectric/Ag/a dielectric) inwhich a dielectric, silver, a dielectric, silver and a dielectric arelaminated in this order.
 15. The glass member according to claim 1 or 3,wherein the antistripping layer comprises silicon oxide, the crystallineundercoat layer comprises zirconium oxide, and the photocatalyst layercomprises titanium oxide.
 16. Double paned glass comprising two glassplates and a spacer placed therebetween so as to create a space betweenthe facing surfaces of the two glass plates, wherein at least one of theglass plates is a glass member according to claim 1 or 3, and thephotocatalyst layer of the glass member is placed such that thephotocatalyst layer serves as an outermost layer of the double panedglass.